Proton Gases offers recertification services for calibration gas cylinders. This service from Proton allows you to recertify expired gas mixtures, verify existing calibration gas mixtures and extend the use of your calibration gases which have expired or reached the end of their certified shelf life. Mostly we are able to upgrade cylinders certification for up to minimum three months and maximum three years (depending on gases compatibility to cylinder wall) following our re-certification process. Contact us at Proton and we shall assist you to check if this service suits your needs.